The meniscus is a C-shaped piece of fibro cartilage that is located at the peripheral aspect of the knee joint, between the femur and the tibia. There are two menisci in each knee, the medial meniscus, and the lateral meniscus. The two menisci absorb shock and spread the force of weight bearing on the joint over a larger area. They also stabilize the ligaments of the knee. The majority of the meniscus has little or no blood supply. For that reason, when damaged, the meniscus does not heal as quickly as other tissue. In addition, the meniscus begins to deteriorate over time, often developing degenerative tears.
Typically, when the meniscus is damaged, the torn piece begins to move abnormally within the joint. Because the space between the bones of the joint is very small, as the abnormally mobile piece of meniscal tissue moves, it may become caught between the femur and tibia. Usually this situation requires that the torn piece be removed. A surgeon can use an instrument, often referred to as a “biter” to remove the tear. The instrument is referred to as a biter because its cutting edges are typically in the shape of a semi-circle or a square and part of jaws that open and close. The cutting edges therefore cut a piece of the meniscus in the shape of a semi-circle or a square when the jaws are closed, giving the appearance of taking a bite.